Bird swing detector

ABSTRACT

Apparatus for inspecting glass containers to determine the presence of the defect termed &#39;&#39;&#39;&#39;bird swing.&#39;&#39;&#39;&#39; Containers to be inspected are moved in series on a moving belt conveyor to an inspection position where a rotating multifaceted mirror causes a beam of light to sweep the container sidewall from bottom to top. If no defect is present, the beam of light passes through the container sidewall. A pair of elongated photosensitive elements are positioned adjacent to the container to view the illuminated wall portion of the container at an angle with respect to the direction of the moving light beam. Should a &#39;&#39;&#39;&#39;bird swing&#39;&#39;&#39;&#39; defect be present, the light beam is deflected from its normal position into one or both of the photosensitive elements. The receipt of a signal by one or the other of these photosensitive elements activates a reject circuit which causes the container having the defect to be rejected from the stream of bottles. The reject mechanism takes the form of a stream of high pressure air under the control of a solenoid valve.

United States Patent ag r 1451 May 16, 1972 [54] BIRD SWING DETECTOR Primary Examiner-Allen N. Knowles [72] Inventor: James Sager Toledo Ohio Attorney-E. J. Holler and D. T. lnms [73] Assignee: Owens-Illinois, Inc. ABSTRACT [22] Filed: Dec, 7,1970 Apparatus for inspecting glass containers to determine the App]. No.: 95,589

presence of the defect termed bird swing." Containers to be inspected are moved in series on a moving belt conveyor to an inspection position where a rotating multifaceted mirror causes a beam of light to sweep the container sidewall from bottom to top. if no defect is present, the beam of light passes through the container sidewall. A pair of elongated photosensitive elements are positioned adjacent to the container to view the illuminated wall portion of the container at an angle with respect to the direction of the moving light beam. Should a bird swing" defect be present, the light beam is deflected from its normal position into one or both of the photosensitive elements. The receipt of a signal by one or the other of these photosensitive elements activates a reject circuit which causes the container having the defect to be rejected from the stream of bottles. The reject mechanism takes the form of a stream of high pressure air under the control of a solenoid valve.

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BMW 3 L? 5 INVENTOR. K/ y Z/ 42%? 2 PATENTEDMAY 16 I972 SHEET H []F 5 BIRD SWING DETECTOR BACKGROUND OF THE INVENTION The detection of the defect in glass containers known as a bird swing has been a continuing problem in the art. This defeet is most prevalent when forming glass containers in the shape of flasks. The bird swing defect is a result of the two sides of the bottle contacting each other during the formation of the parison and prior to the blowing of the container into its final shape. As would be expected, when the two sides of the container touch, the hot, relatively tacky" glass will fuse and as the container is expanded by air under pressure being introduced thereinto, the sides that have touched will move away from each other drawing a small thread of glass therebetween, thus forming what is termed a bird swing.

In the formation of bottles it is necessary to form a parison or preform which is hollow; however, the diameter of the internal space formed in the parison may not be extensive size, particularly in those situations where the container to be formed is of the narrow neck variety. The commonly used Hartford I.S. forming machine forms the parison with the neck down and thus prior to final blowing of the container within a blow mold it is necessary that the parison be inverted. It will be readily appreciated that during the inversion of a relatively hot, elongated, hollow body of glass there is the possibility that the parison will collapse to a slight extent sufficient to cause the internal walls of the parison to touch each other, thus resulting in the formation of a bird swing. The bird swings" are not necessarily characterized in their final shape by the presence of a complete thread running between the two inner walls, it being understood that the thin filament of glass which would span the diameter of the container may break due to its becoming extremely thin and thereby cooling extremely rapidly, to the extent that it would break rather than stretch. However, in every instance when a bird swing is formed, there will be small conical protuberances from the sidewalls in the direction of the opposite sidewall, coincident with the formation of the bird swing.

U.S. Pat. No. 3,438,492 to Albers et al. discloses one form of a bird swing detector. However, the utility of the bird swing detector disclosed in the Albers et al. patent, has been rather limited due to the restriction of the use of the bird swing detector with a plug gauging device. Furthermore, since its light source is of limited size and the area of coverage is limited, only those bird swings" which fall in the area of illumination will be detected. The present invention is a bird swing detector which may be used independently of any other gauging apparatus and which, because of its light scanning arrangement, has the ability of inspecting substantially the entire wall portion of the container.

SUMMARY OF THE INVENTION This invention relates to apparatus for detecting the presence of conical, inwardly extending protuberances in the inside walls of blown glass containers. These protuberances are associated with the glass container-forming defect, known as bird swing."

Containers to be inspected are presented, one at a time, in series, at the inspection station by means of a moving belt conveyor. A rotating multi-faceted mirror directs a light beam through a vertical slit and then through the container sidewall as the container passes through the inspection station. Rotation of the mirror causes the light beam to sweep from the bottom of the container to the top of the container. The speed of rotation of the mirror is such that multiple scans of the container sidewall are made as the container passes by the fixed, vertical slit. If there is no defect present in the container, the light beam passes without deflection through the sidewall and is dissipated. Any protuberances in the sidewall, such as those caused by bird swings, will cause the light beam to be deflected. Photosensitive detection devices are situated at an angle to the light beam on either side of the light beam path, so that any deflection of the light beam by reflection or refraction, will be detected by one or both of the photosensitive devices. Light falling on either photosensitive device will initiate a signal which will actuate a reject mechanism to cause the container to be rejected as defective. In order to avoid erroneous signals being produced by the photosensitive devices, the output signal that is used to initiate the reject mechanism is gated so that the period of inspection is confined to that time when the container profile edges are out of the light beam illumination. One means of rejection is an air blast, controlled by a solenoid valve, to blow the defective container off the moving belt conveyor.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an end elevation view of the apparatus of the invention;

FIG. 2 is a side elevation view of the left side of the apparatus of the invention as shown in FIG. 1;

FIG. 3 is a side elevation view of the right side of the apparatus of the invention as shown in FIG. 1;

FIG. 4 is a top cross-sectional view of the apparatus of the invention taken along line 4--4 of FIG. 1;

FIG. 5 is a perspective view, partially in cross-section, of a portion of one of the photosensitive detection devices of the invention; and

FIG. 6 is a schematic, circuit diagram of the control system of the invention.

DETAILED DESCRIPTION OF THE INVENTION With particular reference to FIGS. 1 through 4, the apparatus of the invention will be described in detail. An endless belt conveyor 10, supported by a suitable bed 12, is used to convey glass containers 14, one at a time in series, through the inspection station. Attached to the conveyor bed 12 is a vertical, generally planar, optic support plate 16. The optic support plate 16 supports a motor 18 whose drive shaft 20 carries a multi-faceted mirror 22. A clamp 24 attached to the optic support plate 16 serves to hold a light source housing 26. The light source housing 26 has disposed within it a source of incandescent light 28 and a lens system 30 for directing the light beam from incandescent source 28 onto the multi-faceted mirror 22. A bracket 32 fixed to the upper end of the plate 16, serves to attach a horizontal support plate 34 to the optic support plate 16. The support plate 34 serves as a convenient mounting plate for a box 36 which contains the necessary electronic logic and discrimination circuits for processing the inspection signals. Also attached to the support plate 34 is a generally vertical detector support plate 38. The detector support plate 38, which is spaced from the optic support plate 16, carries a photocell mounting bracket 40. As best seen in FIG. 3, the mounting bracket 40 serves as a support for two small, spaced apart photocells 42, 44. In opposing relationship to the photocells 42 and 44, is a light source support bracket 46 mounted on the optic support plate 16. As best seen in FIG. 2, two light beam sources 48 and 50 are attached to the light source support bracket 46. The light sources 48 and 50 are positioned so that their beams are parallel and aimed at the photocells 42 and 44, thus acting as a means controlling the period of the gauging function. That is, as may be seen in FIG. 4, the leading and trailing edges of a container 14 to be inspected form relatively thickened portions. If the light beam were to be directed through the leading and trailing edges of the container 14, the light beam might be deflected. Since, in this apparatus, a deflected light beam indicates a defective container, the result would be a false rejection signal. To prevent this from occurring, the combination of the photocells 42 and 44, and the light sources 48 and 50 are positioned to indicate the presence of a container 14in the proper position to be inspected or gauged. The photocells 42 and 44 are positioned such that when the finish or upper portion of a container 14 breaks the light beam from light source 48 to the photocell 44, the rejection and inspection system is made operative. That is, the leading edge of the container 14 has passed the inspection light beam position and will not cause a false rejection signal. When the light beam from light source 50 to the photocell 42 is broken by the trailing edge of the upper or finish portion of the container 14, the gauging and rejection circuits are again turned off, anticipating the arrival of the trailing edge of the container 14 at the inspection light beam area. Thus, the inspection function is disabled when both'the leading and trailing edges of a container 14 are in a position to interfere with the inspection light beam, or when a container is not present to be gauged. Also attached to detector support plate 38 is a bracket 52 which carries a solenoid valve 54 and a nozzle 56 which is screwed into the solenoid valve 54. A pipe 58 connected to the solenoid valve 54 is used to introduce a supply of compressed air into the solenoid valve 54. As best seen in FIG. 3, detection units 60 and 62 are also attached to the detector support plate 38. The detection units 60, 62, each have attached to them a cable supporting plate 64 which serves to carry the output signal leads 66 when bundled into cables from the detection units 60, 62. The location of the output signal leads 66 are best seen in FIG. 5.

Referring now to FIG. 2, a relatively narrow, vertical slit 68 is provided in the optic support plate 16 at the desired gauging location intermediate the length of the optic support plate 16. The light source 28 is focused into a beam by the lens system 30 and directed toward the multi-faceted mirror 22. As the multi-faceted mirror 22 is rotated by the motor 18, the light beam is reflected therefrom through the slit 68 and generally focused onto the rear sidewall of the container 14 in an upward sweep in a scanning manner. The motor 18 is supported by a support bracket 70 which is in turn bolted to the optic support plate 16. The motor support bracket 70 is provided with vertical slots 72 to permit adjustment of the position of the motor 18 and the multi-faceted mirror 22. This adjustment of the motor 18 is necessary to set the upper and lower position of the scanning light beam on the sidewall of the container l4 and is used to make the initial set-up of the gauging apparatus. It should also be noted that the bracket 24 which supports the light source housing 26 may also be loosened so that the light source housing 26 may be moved in a vertical manner. Movement of the light source housing 26 will move the focal point of the light beam such that it may be focused properly on the rear sidewall of a container 14 to be inspected. Again, this adjustment would be made when setting the gauging apparatus for a particular size of container to be inspected. The support bracket 46 is likewise provided with vertical slots 74 to allow for the gauging of containers of varying height. That is, since the light sources 48 and 50 carried by the support bracket 46 must be at approximately the height of the upper or finish portion of a container 14 to be inspected, it is necessary that they be adjusted for containers of varying height. The width of the upper or finish portion of containers 14 to be inspected may also vary, and therefore horizontal slots are provided in the support bracket 46 to allow adjustment of the light sources 48 and 50 for varying widths of the container finish or upper portion. These horizontal slots are not specifically shown. It may be noted when viewing FIGS. 2 and 4, that the longitudinal length of the optic support plate 16 is less than he longitudinal length of the detector support plate 38. Thus, when it is desired to reject a defective container 14, the nozzle 56 is used to blow against the neck of the container 14 and the defective container 14 will be toppled off the conveyor 10.

With reference to FIG. 3, the solenoid valve 54 is shown partially cut away so that the detail of the mounting bracket 40 may be better seen. The mounting bracket 40 is provided with vertical slots 76 corresponding to the vertical slots 74 in the bracket 46, again to allow vertical adjustment for containers of varying heights. The mounting bracket 40 may also be provided with horizontal slots, not shown, again to provide horizontal adjustment of the position of the photocells 42, 44, for containers of varying widths. The detector support plate 38 is provided with a relatively large opening 78 opposite the narrow slit 68 in the optic support plate 16. The opening 78. is

provided to allow any reflected light from defects in the containers 14 being inspected to be reflected into the detection units 60, 62. The detection units 60, 62 are provided with horizontal mounting slots 80 which are used to adjust the position of the detection units 60, 62 in the initial set-up of the gauging apparatus. That is, the detection units 60, 62 may be adjusted in a horizontal manner such that they will receive a reflected or refracted light beam from any defect in a container 14.

Referring now to FIG. 4, it may be seen that the slit 68 in the optic support plate 16 is directly opposite the opening 78 and the detector support plate 38. The light beam directed from the multi-faceted mirror 22 would normally pass through the slit 68, through the sidewall of a container 14 and through the opening 78. However, should an obstruction be present in the container 14, such as that illustrated by a bird swing" 82, the light beam would be deflected into one of the elongated angled slots 84, 86, provided in the detection units 60, 62. The elongated angle slots 84, 86 run the entire vertical height of the detection unit 60, 62, such that any reflection or refraction of the light beam from an obstruction at any height in the container 14 will be detected.

Referring now to FIG. 5, which is a partial perspective view of the detection unit 62, the several elements which comprise the detection unit 62 may be seen more clearly. It should be understood that the detection units 60 and 62 are identical in construction with unit 62 being a right-hand unit and detection unit 60 being considered a left-hand unit. A body plate 88 is provided with an elongated channel 90 which communicates with the angled slot 84. A photosensitive device 92 is positioned in the elongated channel 90 such that any light entering through the angled slot 84 will impinge on the photosensitive device 92. A backing strip 94 is provided to hold the photosensitive device 92 in intimate contact with the angled slot 84. A hold-down plate 96 is provided to hold the photosensitive device 92 and the backing strip 94 in a fixed relationship. The output leads 66 from the photosensitive device 92 exit from the body plate 88 through the slots 98 provided in the body plate 88.

As shown in FIG. 6, any signal from the output leads 66, indicating a defective container which should be rejected, is sent to an amplifier 100 and thence to a gauging system relay 102. The gauging system relay is inoperative until the light beam from the light source 48 to the photocell 44 is broken by the upper or finish portion of a container, thereby indicating that the leading edge of the container is not in a position to cause a false rejection signal and that the body of the container is positioned to be inspected. The gauging system relay 102 remains operative until the light beam from the light source 50 to the photocell 42 is broken by the trailing edge of the upper or finish portion of the container to be inspected, thereby indicating that the trailing edge of the container is about to reach a position such that it might cause a false rejection signal. The gauging system relay 102 then remains inoperative until such time as the next container to be inspected breaks the light beam from the light source 48 to the photocell 44. A signal from the output leads 66 to the amplifier 100 is passed by the gauging system relay 102 and sent to the solenoid valve 54. The signal from the gauging system relay 102 to the solenoid valve 104 will initiate a blast of compressed air, directed to blow the defective container from the stream of containers passing along the conveyor.

1 claim:

1. Apparatus for inspecting containers for bird swings comprising, a horizontal, moving belt conveyor for supporting a plurality of containers to be inspected, a vertical light beam source mounted at one side of said conveyor, a multi-faceted mirror mounted in front of said light source and adapted to reflect a beam of light impinging thereon, a pair of spacedapart vertical plates extending parallel to the conveyor adapted to maintain containers in line in series, one of said plates having a vertical slit formed therein extending from a position slightly above the surface of the belt conveyor to a point corresponding to the shoulder height of the tallest container to be inspected, said mirror and light beam being so positioned relative to said slit that the beam of light is reflected from said mirror through said slit in a direction substantially normal to the plates, a pair of spaced-apart, vertically extending photosensitive elements positioned opposite to said slit in an opening in said other plate, said elements being out of direct line-of-sight of said reflected beam of light, means covering said elements to limit the field of illumination of said elements to vertical paths of reflected or deflected light from a bird swing connection to the adjacent wall of said container and illuminated by said beam of light.

2. The apparatus of claim 1 further comprising, means responsive to a signal from said vertical, photosensitive elements when a beam of deflected light from bird swing" impinges on said vertical, photosensitive elements to generate a rejection signal and means responsive to said rejection signal to reject a defective container from said plurality of containers supported by said moving belt conveyor.

3. The apparatus of claim 2 wherein said means responsive to said reject signal to reject a defective container includes a source of compressed air, a solenoid valve connected to said source, said valve being positioned to impinge air on containers after inspection, whereby a pulse of compressed air will blow a defective container from said moving belt conveyor.

4. The apparatus of claim 2 further comprising, means to condition said reject signal means to pass a signal only when a container is in the proper position for inspection.

5. The apparatus of claim 4 wherein said conditioning means comprises a pair of photocell-light source units positioned to respond to the passage of the neck portion of a container on said conveyor. 

1. Apparatus for inspecting containers for ''''bird swings'''' comprising, a horizontal, moving belt conveyor for supporting a plurality of containers to be inspected, a vertical light beam source mounted at one side of said conveyor, a multi-faceted mirror mounted in front of said light source and adapted to reflect a beam of light impinging thereon, a pair of spaced-apart vertical plates extending parallel to the conveyor adapted to maintain containers in line in series, one of said plates having a vertical slit formed therein extending from a position slightly above the surface of the belt conveyor to a point corresponding to the shoulder height of the tallest container to be inspected, said mirror and light beam being so positioned relative to said slit that the beam of light is reflected from said mirror through said slit in a direction substantially normal to the plates, a pair of spaced-apart, vertically extending photosensitive elements positioned opposite to said slit in an opening in said other plate, said elements being out of direct line-of-sight of said reflected beam of light, means covering said elements to limit the field of illumination of said elements to vertical paths of reflected or deflected light from a ''''bird swing'''' connection to the adjacent wall of said container and illuminated by said beam of light.
 2. The apparatus of claim 1 further comprising, means responsive to a signal from said vertical, photosensitive elements when a beam of deflected light from ''''bird swing'''' impinges on said vertical, photosensitive elements to generate a rejection signal and means responsive to said rejection signal to reject a defective container from said plurality of containers supported by said moving belt conveyor.
 3. The apparatus of claim 2 wherein said means responsive to said reject signal to reject a defective cOntainer includes a source of compressed air, a solenoid valve connected to said source, said valve being positioned to impinge air on containers after inspection, whereby a pulse of compressed air will blow a defective container from said moving belt conveyor.
 4. The apparatus of claim 2 further comprising, means to condition said reject signal means to pass a signal only when a container is in the proper position for inspection.
 5. The apparatus of claim 4 wherein said conditioning means comprises a pair of photocell-light source units positioned to respond to the passage of the neck portion of a container on said conveyor. 